Automated slitting system



Jan- 5, 1970 M. A. KEYES ET AL 3,488,479

AUTOMTED SLITTING SYSTEM Filed Jan, I., 1966 4 Sheets-Sheet l Ofe A rl

M A. KEYES ET AL 3,4%,479

AUTOMATED SLITTING SYSTEM i, 1966 4 Sheets-Sheet 4 jan.. 6, E970 Filed Jan.

'United States Patent C) ILS. Ci. 23S-151.1 9 Claims ABSTRACT F THE DISCLOSURE A slitter system for sheet materials for dividing a web of paper fed from a supply roll into two or more narrower webs so as to provide minimum waste of paper. A computer compares the orders with the width of the master roll and determines the optimum positioning of slitter motors so as to sufficiently utilize the paper.

This invention relates generally to a slitter system for sheet materials and more particularly to a system wherein a web of paper or the like fed from a supply roll is separated into two or more narrower webs which may then be wound on separate rolls. More specifically, the present invention is related to an automatic slitting system which performs many of the functions heretofore accomplished manually.

Winding mechanisms which are employed for winding, slitting and rewinding a web material operate in a discrete fashion; that is, they generally accept only one large roll at a particular time which is then unwound and slit into one or more separate smaller rolls, The actual slitting process is accomplished by the shearing action of a plurality of opposed rotating blades. A different set-up is required of the Winder in accordance with customer demands a-nd in accordance with changes in the characteristics of the web being severed. Therefore, due to the discrete operation of such winding mechanisms, a portion of the available time is utilized in the unproductive phases of replacing large rolls, changing the slitter settings in a cross-web dimension subject to customer demands, replacing cores for the narrow rows, and a variety of other functions with respect to the marking and storing of the smaller rolls.

A system which greatly simplifies the operation of the Winder and the slitter mechanism is described in U.S. Patent No. 3,176,566 to H. R. Patterson, Ir. The system of this patent replaces manual positioning of the slitting devices with a precision remote positioning unit. Although the time of set-up and operation is greatly reduced with the system described in the aforementioned patent, such saving in time is not reduced to absolute minimum due to the necessity of an operator having to refer to production schedule sheets to determine the position of the slitters for a subsequent operation. Furthermore, additional delays resulted from the necessity of the winder operator having to manually mark the rolls with order designation, shipping information, warehouse storage, and other pertinent data.

Another, although related, problem is that of optimally scheduling the sequence in which the rolls are to be severed and in determining what pattern or arrangement of the slitters in a cross-machine direction shall be used in the slitting operation. Originally, this operation was accomplished purely by manual techniques. A human scheduler would arrange the orders of a given grade of paper or the like product with the object of attempting to reduce the trim waste. The trim waste is that portion of the larger roll which is not employed when it is divided by slitting to the customers small roll requirements- This method is slow and generally does not produce a cutting ICC pattern where the minimum amount of waste is achieved.

Therefore, an object of the present invention resides in the provision of a digital computer or large scale analogue trim computer to automatically adjust the position of one or more slitters.

Still another object of the present invention resides in the provision of a unit for marking the finished rolls with information such as order data, shipping data, and warehouse storage location.

These and other objects, features, and advantages of the present invention will be more fully realized and understood from the following detailed description when taken in conjunction with the accompanying drawings wherein:

FIGURE 1 diagrammatically illustrates in block form one embodiment of the present invention wherein digital control is employed in a slitter system;

FIGURE 2 diagrammatically illustrates in block form another embodiment of the present invention wherein analogue information is employed to controll the slitter system;

FIGURE 3 diagrammatically illustrates in block form still another embodiment of the present invention;

FIGURE 4 diagrammatically illustrates in block form a relatively simple embodiment of the present invention;

FIGURE 5 diagrammatically illustrates in block form the simplest embodiment for automatic control of a slitting system; and

FIGURE 6 is a schematic illustration of the electrical circuit diagram of the slitter positioning mechanisms of the present invention.

AS SHOWN ON THE DRAWINGS With reference to the drawings in detail and in particular to FIGURE 1, there is shown an automatic slitter setting, roll marking, and roll allocation system constructed in accordance with the principles of the present invention. A digital computer 11 is supplied with and sorts information from a plurality of punched cards 12. Information on the cards 12 is derived from order data sheets indicated generally by the reference number 13. The order data sheets 13 include the customers name, the finished size of roll required, and other pertinent dataas found on standard order forms.. This information must be reduced to compatible information on a suitable medium, such as the cards 12, which will allow interpolation of such information by the digital computer 11.

After sorting and reading the information on the cards 12, the digital computer 11 delivers output signals in digital form to a display unit and control console 14 through a line 16. Display unit 14 may be a line printer, cathode ray tube, or banks of lights located on the control console. The display unit 14 may -be employed to indicate the position of any slitter for a subsequent slitting operation, customer identification, and/or grade of the paper being slit. The display unit 14 may, if desired, be similar to that provided with conventional digital draw display units. Selector switches 14a and 14'b are provided on the control console; the switch 14a being numn bered from one to the number of slitters in the system and the switch 14b being numbered from one to three. The switch 14h is employed for controlling the mode of display. In the preferred embodiment, the slitter position from the sheet edge or from some arbitrary base point of each slitter can be displayed in mode one by selecting the particular slitter number on the switch 14a. The second position of switch 14b could provide the roll width corresponding to the selection of a given number on the selector switch 14a. The third position of the switch 14b could provide a display of the trim loss from the paper web. In this mode, the percentage of trim loss on each pattern could be displayed. In addition, the switch 14a could be made inoperative, if desired, or could be used to select various displays such as inches lost, tons lost, percentage lost, lost product value in dollars, etc. with respect to the trim loss of the paper web.

The control console 14 further includes a set of switches, designated generally with the reference numeral 14C, for feeding information to the computer 11 not theretofore available from the cards 12. Such manually fed information would readjust the computer 11 accordingly. This information may include, for example, changes in available trim width resulting from a reduced Fourdrinier wire width or terminal felt width. These and other factors would result in less useable paper are supplied to the computer 11 on a line 17 for integration with the information derived from the cards 12.

A manual input station, indicated generally by reference numeral 18, is connected to the digital computer 11 through a line 19 for manually inserting into the computer 11 such information as warehouse storage space availability. Information such as order data, shipping data, and customer code numbers is delivered to the digital computer 11 by way of the punched cards 12 and is delivered to a marking unit through a line 21. Furthermore, warehouse storage data from the manual input station 18 also passes through computer 11 to the marking unit 20. Therefore, the marking unit 20 prints a label or prints directly on the paper web all the pertinent data necessary for proper handling. The label is then iixedly secured to the particular roll corresponding to the information on the label prior to shipment of the rolled web to warehouse storage.

Command signals from the digital computer 11 are delivered to a slitter control 22 through a line 23. The slitter control 22 derives suitable control information indicative of digital command signals to control the operation of a plurality of slitter motors 24. Control signal information from the slitter control 22 is delivered to the slitter motors 24 via a line A26, and feedback information indicative of the actual position of the slitter is applied to the slitter control 22 from the slitter motors 24 via a line 27. The slitter motors 24 may have associated therewith one or more positive sensing means to derive a feedback signal indicative of actual slitter position in such a manner as is well known in the art. Furthermore, the slitter control 22 includes suitable means which convert the actual position feedback signal to corresponding digital signal information which, in turn, is fed back to the computer 11 through a line 28.

yConnected to the slitter control 22 is a manual entry control 29 which actuates the slotter control 22 through a line 30. The manual entry control 29 may be used to override any or all of the command signals delivered to the slitter control 22 from the compter 11. The spacing between a slitting band and the corresponding slitting blade of a web slitting apparatus is controlled by a manual entry control 31 which delivers signal information to the slitter control 22 through a line 32 in such a manner as to control the distance between a slitter band and a corresponding slitter blade in increments of 0.0001 inch.

In operation, the plurality of punched cards 12, each corresponding to a particular customer order, is fed into the digital computer 11 whereupon all of the cards are interpreted simultaneously. The information from the cards 12 is placed into a temporary storage. Information indicative of the useable width of the master roll being divided into smaller rolls is also fed into the digital computer 11. The stored information from the punched cards 12 is then processed in such a manner as to select the combination of orders to be filled which will yield the least amount of trim waste from the master roll.

By way of example, it may be desired to divide a master fell having a useable width ef 120 inches. Pour punched cards 12 representing four different customer orders, each requiring a rolled web of a different width may lbe delivered to the computer 11. The computer 11 evaluates the various combinations of web widths requested by the customers and selects the combination of orders to be filled which yields the minimum waste when slitting the master roll. The four widths may correspond to 24 inches, 30 inches, 36 inches, and 72 inches. Only one combination of the orders to be filled will produce maximum eiiiciency of the 120 inch master roll. The combination of the 24 inch, 30 inch and 36 inch rolls will produce a total width of inches to be split from the master roll leaving 30 inches of unused roll which may or may not be used to fill a subsequent order. Furthermore, the combination of 30 inches, 36 inches, and 72 inches provides a total width of 138 inches which exceeds the total useable width of the master roll. On the other hand, a combination of 72 inches and 36 inches yields a useable width of 108 inches thereby providing a waste width of only l2 inches.

Therefore, digital information corresponding to the orders for the 36 inch and the 72 inch width rolls will be propagated from the digital computer 11 to the slitter control 22 which, in turn, positions the corresponding slitters as necessary. The slitters which are not required for the slitting of a particular combination of rolls from a master roll may be positioned at some remote location so as not to interfere with the operation of the slitters used to divide the master roll. That is, a web transport slitting apparatus may be provided with six or more slitters, and in accordance with the example hereinabove, only three slitters are required to divide the master roll into a 36 inch width and a 72 inch width. However, a fourth slitter may be used to trim the unuseable portion of the web thereby placing the 12 inch width remainder of the roll in usable condition.

Shown in FIGURE 2 is an automatic slitter setting system using an external analogue comparator. A computer 41 receives a plurality of punched cards 42 which contain information, such as available trim or order data, from sheets indicated by the reference numeral 43. The computer 41 is connected to a selector unit 44 which performs to actuate one of a lirst plurality of switches 50-55 and a corresponding one of a second plurality of switches 57-62. A switch 49 is provided with one contact 46 thereof connected between the selector 44 and the switches 50-55 and the switches 57-62. Another contact 48 of the switch 49 is connected to a manual selection station 47. By operation of the switch 49, the switches 50-55 and the switches 57-62 may be operated either automatically from the computer 41 or manually from the station 47 Digital information from the computer 41 is delivered to a digital to analogue converter 63 through a line 64. The converter 63 changes the digital information to analogue form for use by a summer amplifier 66. Signal information corresponding to a slitter position is delivered to the analogue summer amplifier 66 through a line 68 from a selector switch 69 when engaged with a contact 70. Signal information corresponding to a slitter position is derived from the digital to analogue converter 63 and represented as a direct current voltage from 0 to 50 volts and applied to the contact 70 through a line 71. A 50-volt source is connected through a potentiometer 72 to a contact 73 to provide a manual mode of operation for positioning the respective slitters.

With one of the switches 50-55 closed, signal information corresponding to the actual position of a corresponding` slitter is delivered to the analogue summer amplifier 66 through a line 76. The analogue summer amplifier 66 then compares the signal information applied thereto through lines 68 and 76 to develop an output signal corresponding to the difference or error between the actual position of the slitter and the desired position of the slitter. This error signal is delivered to an analogue to digital converter 77 through a line 78. The signal information from the analogue to digital converter 77 is then fed back to the digital computer 41 through a line 75.

The error signal information from the output of the analogue summer amplifier 66 is also fed through one of the switches 57-62, corresponding to the particular slitter being positioned, to one of a plurality of amplifiers 79, 80, 81, 82, 83, and 84, The error signal information is delivered to one of the corresponding power amplifiers 79-84 to drive the corresponding slitter drive motor indicated generally by reference numeral 86.

In operation, customer order information is punched into the plurality of cards 42 and fed into the computer 41 in much the same manner as mentioned hereinabove. In the automatic mode of operation, the movable contactor 49 engages the stationary contact 46 and the selector 44 actuates one of the switches 50-55 and one of the switches 57-62. By way of example, the switch 50 and the switch 57 may be closed providing a signal indicative of the position of the first slitter on the line 76 and providing an error signal to the amplifier 79. Signal information corresponding to the actual position of the first slitter is delivered to the amplifier 66 wherein the signal information is compared with signal information corresponding to the desired new position of the slitter and a corresponding error signal is developed at the output of the amplifier 66 and applied to the power amplifier 79 through the switch 57. The amplifier 79 then drives the appropriate slitter drive motor to move the corresponding slitter until the demanded position from the computer 4 1 is equalized by the feedback signal on line 76. At thls time, the signal information from the analogue summer amplifier 66 is zero. The zero reading from the output of amplifier 66 is then delivered to the digital computer 41 through the analogue to digital converter 77 and the line 75 thereby generating a suitable shift signal to open switches 50 and 57 and close switches 51 and 58 so as to position the second slitter. Prior to the generation of such a shift signal, however, a tighten signal is provided for tightening a slitter band against a corresponding slltter blade. The operation of positioning the second and subsequent slitters is substantially the same as .the operation of positioning the rst slitter mentioned heremabove.

In the manual mode of operation, the selector swltch 49 may be placed in contact with stationary Contact 48 and suitable manual means may be provided to selectively energize corresponding switches 50 and 57, 51 and 58, 52 and 59, 53 and 60, 54 and 61, 56 and 62. Also in the manual mode of operation the selector switch 69 may be placed in contact with stationary contact 73 and an analogue signal corresponding to a slitter positron may'be applied to the analogue summer amplifier 66 by varying the potentiometer 72.

A unit 85 provides a signal to the computer 41 whenever one slitter position interferes with another adjacent slitted position. A console on the computer 41 may be employed for indicating not only such a position interference, but such information as that provided by the display unit 14 of FIGURE 1.

Shown in FIGURE 3 is a simplified form of an automatic slitter setting system wherein all comparison signals are derived internally of the computer. A computer 91 receives a plurality of punched cards 92 which, in turn, are processed to include order or trim data from order forms such as indicated by reference numeral 93. Feedback information indicative of the actual position of each of the slitters is fed to an analogue to digital converter 94 through a plurality of lines 96, 97, 98, 99, 100, and 101. Each of the lines 96-101 may be provided with suit-able selective means to apply the signal information to the analogue to digital converter 94 selectively one at a time. However, the analogue to digital converter 94 may include selector means therein, thereby obviating the need of external selector means.

The output of the analogue to digital converter 94 is delivered to the digital computer 91 through a plurality of lines 102, 103, 104, 105, 106, and 107. Each of the lines 102-107 correspond to a particular slitter, and signal information corresponding to the position of each slitter may be individually selected and compared with the desired position of the particular slitter and an error signal developed within the digital computer 91. The error signal corresponding to the new slitter position is then delivered to each of the slitters through a plurality of lines 108, 109, 110, 111, 112, and 113 from the output of computer 91.

The digital computer 91 is provided with a priority interrupt means which is applied thereto through a line 114. The priority interrupts signals any interference between adjacent slitters.

Shown in FIGURE 4 is another embodiment in simplified forim of an automatic slitter setting system 0f the present invention. A digital computer 121 receives information from the plurality of punched cords 122 which, in turn, have order data applied thereto from order sheets, such as indicated by the reference numeral 123. Each of the sl-itters have suitable feedback means to develop digital signal information indicative of the actual position of the slitter. These feedback signals may be derived from a gear driven shaft position encoder or digital position transducer secured to each slitter. Such digital signal information is supplied to the digital computer 121 through a plurality of lines 126, 127, 128, 129, 130, and 131. Actual positions of the feedback signals in the form of a digital signal information obviates the need of analogue to digital converters as shown in FIGURE 3.

The computer 121 compares the desired position of each slitter with the actual position thereof to develop an error signal at the output of the computer 121 which is delivered to respective ones of the slitter positioning controls through a plurality of lines 132, 133, 134, 135, 136, and 137. The slitters may be controlled by stepping motors responsive to the digital signals on lines 132-137 and/ or by clutch controls responsive to the digital signals. Priority interrupt means are provided for supplying signal information to the computer 121 through a line 138 whenever slitter interefrence ocours.

Shown in FIGURE 5 is a further modification of a more simplified automatic slitter setting system. A digital computer 141 is provided to receive a plurality of punched cards 142 which, in turn, have order data applied thereto from order sheets, such as indicated by the reference numeral 143. The output of computer 141 is delivered to respective slitter positioning controls through a plurality of lines 146, 147, 148, 149, 150, and 151 to control the position of the respective slitter associated with each of the lines. In this simplified form of the invention, no feedback information is required to give actual position signals from the slitters, The movement of the slitters is controlled by stepping motors applied thereto. The movement of each slitter originates from a given reference point and the digital computer 141 merely keeps track of the number ofl pulses applied to each one of the stepping motors.

The digital computer 141 may have a plurality of manual inputs such as a selectable index input, a slitter tightening input, and a slitter inoperative input. The manual index input selects the starting point for all of the slitters so that the digital computer 141 can keep track of the movement of the slitters relative to a starting point. The slitter tightening input merely adjusts the relative position between the slitter blade and the slitter roller in increments of 0.0001 inch. The slitter inoperative input manually places any unused slitters in an inoperative state so as not to interfere with the normal operation of the slitter apparatus.

Shown in FIGURE 6 is still another embodiment of an automatic slitter setting system and is shown used in conjunction Wit-h a remote position control system. The

remote position control system as shown in FIGURE 6 is similar to that shown in the patent issued to HR. Patterson, Ir., Patent No. 3,176,566. A digital computer 161 is provided for receiving a plurality of punched cards 162 which, in turn, receive order data from sheets generally indicated by the reference numeral 163.

A pair of digital stepping motors 164 and 166 are connected to outputs of the digital computer 161. The motors 164, 166 are provided with output shaft 167 and 1968, respectively, the angular position of each being indicative of outputs from the computer 161. The output shaft 167 drives a selsyn generator 169 which is connected to a control transformer 170 having an output signal indicative of the position of the shaft 167 The output of the control transformer 170 is connected to an amplifier 171 which provides a feedback signal on lines 172 and 173 to an analogue to digital converter 174. The analogue information from the amplifier 171 is converted to digital information and is supplied to the digital computer 161. The output of the amplifier 171 controls the position of slitter band.

In a similar manner, the output shaft 168 of the motor 166 is connected to a selsyn generator 177 which provides an output signal from a corresponding control transformer 178 to an amplifier 179. The amplifier 179 is connected by leads 180 and 181 to the analogue to digital converter 174 for providing a feedback signal to the digital computer 161. The output of the amplifier 179 controls the position of the slitter blade in accordance with signals provided from the digital computer 161 to the stepping motor 166.

As described in the patent to H. R. Patterson, Jr., Patent No. 3,176,566, the slitter blade and slitter band are each supported on respective carrier members. These carrier members are slidably mounted on respective rails which extend in the cross-machine directionfor positioning the respective slitter band and slitter blade. It is to be understood, however, that other positioning structures may be employed. A positioning motor 182 (FIG URE 6) is mounted on the carrier member which supports the band and a positioning motor 183 is mounted on the carrier which supports the blade. The tmotors 182, 183 are connected through on-off switches 184a and 184!) to a pair of terminals 186 and 187 disposed for connection to a source of power. During the positioning operation of the slitter band and the slitter blade, the switches 18411, 184!) are maintained closed for continuous operation of the positioning motors 182, 183.

An output shaft of the motor 182 is connected through a gearbox and through a forward and a reverse clutch 188 and 189 to a pinion which engages a rack secured to the respective rail. In this manner, energization of one of the clutches 188, i189 engages the output shaft of the motor 182 through the gearbox to the rack and the pinion for moving the slitter band along the rail. The positioning motor 183 for the blade is similarly connected through a gearbox and through a forward and a reverse clutch 19t) and 191 to a pinion which engages a rack secured to the rail which supports the blade thereon.

The clutches 188, 189 are energized by the amplifier 171 which is connected to an output of the control transformer 1170. Similarly, the clutches 190, 191 are connected to the output of the amplifier 179, which output is proportional to the output of the control transformer 178. A rotor 192 of the control transformer 170 and a rotor 193 of the control transformer 178 are each connected to respective pinions and, when rotated therewith, decrease the outputs of the respective control transformers 170, 178 until a zero output is reached and the respective clutches 188-1911 are deenergized.

In operation, therefore, the stepping motor 164 is driven in accordance with signals from the 'digital computer 161 and angularly positions a rotor 194 of the selsyn generator 169 in accordance with such signals. Angular movement of the rotor 194 produces an output from the control transformer which is proportional to the angular displacement of the rotor 194. This output is amplified and controls energization of a respective one of the clutches i188, 189. Energization of one of the clutches 188, 189 moves the carrier member along the rail and, at the same time, changes the angular position of the rotor 192 of the control transformer 170. As the rotor 192 is displaced angularly an equal amount to the angular displacement of the rotor 194, the output of the control transformer 170 reduces to a zero condition. Therefore, positioning of the band on the rail is provided in accordance with output signals from the digital computer 161 to the stepping motor 164.

Energization of the stepping motor 166 controls the positioning of the slitter blade in a like manner to the slitter band positioning structures. A rotor 196 of the selsyn 177 is angularly displaced by the stepping Imotor 166 in accordance with signals from the digital computer 161. The control transformer 178 provides an output in accordance with the angular displacement of the rotor 196 `which is amplified by the amplifier 179 to energize the clutches 190, 191. Energization of one of the clutches 190, I191 positions the carrier member which supports the blade on the rail and, at the same time, changes the angular position of the rotor 193 of the control transformer 178. When the rotor 193 has been displaced the same as the angular displacement of the rotor 196, the output of the control transformer 178 is reduced to a zero condition to deenergize the clutches 190, 191.

An output of the control transformers 170, 178 is also supplied through the respective amplifiers 171, 179 to the analogue to digital converter 174 for providing feedback information to the digital computer 161 of the actual position of the slitter band and the slitter blade on the respective rails. Each of the amplifiers 171, 179 should include a phase-sensitive detector for indicating the direction of rotation of the rotors 192, 193 and for proper energization of a respective one of the clutches 18S-191 for movement of the carrier members in the correct direction along the rail.

The stator windings of the selsyn generator 177 are connected to respective stator windings of the control transformer 178 through switches 197, 198 and 199 in one position of the switches 197-199 as shown in FIG- URE 6. In another position of the switches |197-199 the stator windings of the control transformer 178 are connected to the stator windings of the selsyn generator 169. This connection of the selsyn generator 169 to the control transformer 178 controls the position of the blade in accordance with the angular displacement of the rotor 194. In a third position of the switches 197-199 the stator windings of the control transformer 178 are connected to the stator windings of a selsyn generator 200 having a rotor 201 thereof mechanically coupled to the rotor 192 of the control transformer i170 and to the pinion which positions the slitter band. This connection of the selsyn generator 200 to the control transformer 178 causes the slitter blade to follow the movement of the slitter band precisely.

It is often desirable to employ a plurality of pairs of slitter units in conjunction with a single winding apparatus. In such instances, each slitter blade is mounted on the same rail with one another and each slitter band is mounted on another rail with one another. With more than one unit mounted on a single rail, it is necessary and desirable to automatically deenergize the drive units of the slitters when one is moved against and interferes with the other. Furthermore, it is desirable to deenergize the drive when the slitters reach a certain limit of travel in one direction or another in the cross-machine direction.

According to this invention, a piar of switches 202 and 203 are mounted on opposite sides of the carrier member which supports the band and the motor 182 thereon. The switches 202, 203 are disposed for engaging 9 either a fixed stop or an adjacent carrier member and opening upon such engagement to deenergize the corresponding clutch 188, 189.

As shown in FIGURE 6, the switches 202, 203 are respectively connected between the amplifier 171 and the forward clutch 188 and the reverse clutch 189. Similarly, a pair of switches 204 and 206 are respectively connected between the amplifier 179 and the forward clutch 190 and the reverse clutch 191. The switches 204, 206 are mounted on opposite sides of the carrier which supports the blade and the positioning motor 183 thereon and are disposed for engaging either a fixed stop of an adjacent Ablade carrier member. The switches 202, 203, 204 and 206 are connected to a priority interrupt unit 207 which provides corresponding signals to the digital computer 161 to indicate an interference between adjacent slitter units. The digital computer 161 may be provided with a read-out console for indicating such slitter interference, if the computer 161 is not capable of correcting the difficulty.

Means are provided for locking the carrier members onto the rails when the correct position of the slitter band and the slitter blade has been achieved. When the desired position has been achieved, feedback information from the amplifiers 171, 179 signals the digital computer 161 to open the on-off switches 184g, 184b to deenergize the positioning motors 182, 183. A relay 208 is also connected through the switches 184a, 18419 to the source of power on the terminals 186, 187, which relay includes a plurality of normally closed switches 209, 210, 211 and 212.

A current source is connected to a pair of terminals 213 and 214 and the switches 209-212 are each connected between the terminal 213 and one of the clutches 18S-191. The terminal 214 is connected to a common line of each of the clutches 18S-191. When the on-off switches 184a, 184b are closed, such as during the positioning operation of the slitter units, the rnotors 182, 183 are energized and the relay 208 is also energized to maintain the switches 209-212 open for disconnecting the source of current at the terminals 213, 214 from the clutches 18S-191. However, when the on-off switches 18451, 18411 are open, the positioning motors 182, 183 and the relay 208 are deenergized, Which deenergization of the relay 208 causes closing of the switches 209-212 to connect the source of current at the terminals 213-214 to the clutches 188-191. With the clutches 188-191 energized and with the motors 182-183 deenergized, the slitter units are locked in position because of high frictional resistance to rotation due to a large speed reduction in the gear reducing units of each motor.

Individual drive motors may ybe employed for driving the band and the blade of each slitting unit or, if desired, the blade may be rotated by frictional engagement with the band. In the latter case, the blade must be tightened against the band for effecting the frictional drive thereof. Therefore, before the positioning motors 182, 183 lock the carrier members on the respective rails, it may be necessary to move the positioning motor 183 one or more small increments. For effecting such move-` ment, a tightness'input 216 is provided which is connected to the motor 166 to cause a small increment of movement of the blade with respect to the band.

The slitter setting system of the present invention may take other forms because of the computer control employed as described above. One such form or modification involves replacing the selsyn generators 169, 177 and the control transformers 170, 178 with an electronic feedback device which senses the position of each slitter unit. The stepping motors 164, 166 in this form of the invention would be connected directly to the slitter blade and slitter band respectively. Also, the stepping motors 164, 166 would be connected to the computer 161 to provide precision settings of the slitters. This form of the invention eliminates a major fraction of the required control equipment illustrated in FIGURE 6, since these functions would be accomplished internally in the digital computer 161. An even simpler form of this system (and thus less expensive and more reliable) would be one in which no feedback regarding position whatsoever would be employed. In such a version of the present invention, precision stepping motors would drive the slitters and the position of the slitters would be determined by maintaining an algebraic sum of the pulses supplied to the slitter in a storage of the computer memory. This sum is linearly related to the position from a zero point which can be defined arbitrarily.

The system of this invention is particularly advantageous in combination with the illustrated form of the slitter structure shown in U.S. Patent No. 3,176,566, wherein the blade is in the form of an essentially at disk having opposed surfaces connected by a tapered or conical peripheral surface which defines a sharp cutting edge. The peripheral edge portion of the surface engages a peripheral edge portion of the lower band to obtain the shearing action. As previously mentioned, the band may drive the blade by a frictional engagement therewith and, therefore, means are provided for supplying small incremental pulses to the blade stepping motor 166 for tightening the slitter blade against the corresponding slitter band to facilitate the frictional engagement between the two. This tightness input may be controlled by the computer 161 upon the occurrence of a zero feedback delivered thereto or may be controlled manually, if desired.

Although a specific embodiment of the invention has been described herein, it is not intended to limit the invention solely thereto, but to include all of the obvious variations and modifications Within the spirit and scope of the appended claims.

We claim as our invention:

1. A system for controlling the position of a plurality of slitter units disposed for dividing a supply roll of We'b material into at least two smaller rolls in accordance with ldemanded size requirements, comprising a computer responsive to a plurality of inputs each corresponding to a respective demanded size requirement and for selecting a group of `said inputs which provides a minimum amount of waste when the supply roll is severed in `accordance with the `demanded size requirements of said group of inputs, a plurality of positioning motors with each one connected to a respective one of the slitter units and responsive to the 'selected inputs from said computer for positioning said units in accordance with the size requirements of the selected inputs, including a pair of digital stepping motors connected to outputs of said computer and each having a shaft output proportional to the selected group of inputs, and means for energizing each of said positioning motors in accordance with the shaft output of the respective one of said stepping motors.

2. A system for controlling the position of a plurality of slitter units disposed for dividing a supply roll of Web material into at least two smaller rolls in accordance with demanded size requirements, comprising a computer responsive to a plurality of inputs each corresponding to a respective demanded size requirement and for selecting a group of said inputs which provides a minimum amount of Waste when the supply roll is severed in accordance with the demanded size requirements of said group of inputs, a plurality of positioning motors with each one connected to a respective one of the slitter units an-d responsive to the selected inputs from said computer for positioning said units in accordance with the size requirements of the selected inputs, including means for sensing the position of each lslitter unit from a reference point and providing `feedback signals indicative of such positions to said computer, said computer being responsive to said feedback signals for energizing said positioning motors.

3. The system as defined in claim 3 wherein said sensing means includes a pair of shaft position encoders each connected to a respective one of said positioning motors.

4. The system as defined in claim 3 inclu-ding an analogue to digital converter responsive to said encoders and connected to said computer for supplying feedback signals thereto from said encoders proportional to the position of each slitter unit from a reference point.

5. A system for controlling the position of a plurality of slitter units disposed for dividing a supply roll of web material into at least two smaller rolls in accordance with demanded size requirements, comprising a computer responsive to a plurality of inputs each corresponding to a respective demanded size requirement and for Vselecting a group `of said inputs which provides a minimum amount of waste when the supply roll is severed in accordance with the demanded size requirements of said group of inputs, a plurality of positioning motors with each one connected to a respective one of the slitter units and responsive to the selected inputs from said computer for positioning said units in accordance with the size requirements of the selected inputs, wherein said computer provides digital pulses at outputs thereof and said positioning motors being responsive to each of said pulses for moving a respective slitter unit a predetermined distance, said comptuer including memory means for storing the number of pulses supplied to said positioning motors and comparing that number with the demanded size requirements.

6. A system for controlling the position of a plurality of slitter units disposed for dividing a supply roll of web material into at least two smaller rolls in accordance with demanded size requirements, comprising a computer responsive to a plurality of inputs each corresponding to a respective demanded size requirement and for selecting a group of said inputs which provides a minimum amount of waste when the supply roll is severed in accordance with the demanded size requirements of said group of inputs, a plurality of positioning motors with each one connected to a respective one of the slitter units and responsive to the selected inputs from said computer for positioning said units in accordance with the size requirements of the selected inputs, including a -digtal to analogue converter connected to outputs of said computer, an analogue summer connected to outputs of said converter and connected to each of said positioning motors, and feedback means having outputs indicative of slitter positions connected to said summer.

7. The system as dened in claim 6 including an analogue to -digital converter connected from an output of said summer to said computer.

8. A system for controlling the position of a plurality of slitter units disposed for dividing a supply roll of web material into at least two smaller rolls in accordance with demanded size requirements, comprising a computer responsive to a plurality of inputs each corresponding to a respective demanded size requirement and for selecting a group of said inputs which provides a minimum amount of waste when the supply roll is severed in accordance with the demanded size requirements of said group of inputs, a plurality of positioning motors with each one connected to a respective one of the slitter units and responsive to the selected inputs from said computer for positioning said units in accordance with the size requirements of the selected inputs, including a plurality of stepping motors connected to said computer and having shaft outputs proportional to said group of inputs, a plurality of selsyn generators each connected to a respective one of said stepping motors, a plurality of control transformers each responsive to a respective one .of said generators, a plurality of amplifiers each connected to an output of a respective one of said transformers, each of said positioning motors being responsive to outputs of a respective one of said amplifiers.

9. The system as dened in claim 8 including a plurality of clutches each connected between a respective one of said positioning motors and a respective slitter unit, each of said clutches being connected to outputs of a respective one of said amplifiers, each of said ampliers including a phase-sensitive detector.

References Cited UNITED STATES PATENTS 2,873,439 2/1959 Lahti et al 340-347 3,165,952 l/l965 Thompson et al. 83-71 3,176,566 4/1965 Patterson 83--348 3,261,012 7/1966 Bentley 340-347 3,272,975 971966 Csech 23S-151.11` 3,292,495 12/1966` Hill et al. 90-13.5 3,239,738 3/1966 Welch 318-138 EUGENE G. BOTZ, Primary Examiner JOSEPH F. RUGGIERO, Assistant Examiner U.S. Cl. XR. 83-71 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 488, 479 Dated January 1970 1nvent0r(5) MARION A. KEYES and ROBERT A. BEACHLER It is certified that error appears in the above-:Identified patent and that said Letters Patent are hereby corrected as shown below:

Column I, line 5, after "53511", insert assignors to Beloit Corporation, Beloit, Wisconsin, a corporation of Wisconsin".

Column 3, line 51, change "slotter" to s1itter.

Column 6, line 20, Change "cords" to Cards.

Column 7, line lO, change "1968" to 168.

Column 8, line 72, change "piar" to "pair".

Column 11, line 1, change "3" to 2; line 27, change "comptuer" SIGNED AND SEALED AUG 251970 (SEAL) Attest:

Edmd M- Mk mnu r. JR- Msging Ofeer @omissione'r of Yam FORM PO-105O (io-69D uscoMM-nc scavo-pes U S GOVERNMENT PIIII'ING OFFICE: IDI 0-3illl 

